The present invention pertains to an air inflation control system for adjusting the air pressure within an inflatable device. More particularly, the present invention pertains to a microprocessor based system for monitoring the air pressure within an inflatable device and controlling the supplying of air to and venting of air from the inflatable device, as needed. The system can be implemented in a manner requiring insertion of one or more coins to enable activation, if desired. Further, this system can provide other air-related options, such as a vacuum cleaning capability.
Optimum operation of automobiles and trucks requires that the tires of such vehicles be inflated to a proper level. If the inflation level is lower than it should be, excessive fuel is consumed by the vehicle, and the tires wear out faster. If the inflation level is too high, tire wire is accelerated and the vehicle rides uncomfortably. To permit their customers to adjust their tire pressure, automobile service stations frequently have available for their customers a controlled, pressurized air supply, enabling the customers to add air to or vent air from truck and automobile tires as well as other inflatable devices such as bicycle tires, air mattresses, footballs, basketballs, and other such things. Frequently such air supply consists simply of an adjustable control enabling the customer to set the desired air pressure, and a hose connected to a pressurized air source and terminating in a valve adapted to mate with the air valve of an automobile tire. The accuracy of such air supplies is somewhat low, and the air supply can take an undesirably long time to inflate an inflatable device to a desired air pressure. Additionally, most such air supplies are incapable of automatically venting air from the inflatable device when the actual air pressure in the device is greater than the desired air pressure. Instead, air must be vented manually until the actual air pressure is below the desired air pressure, and then the device must be reinflated to the desired air pressure. Further, such air supplies generally have only one supply rate. Large volume devices, such as automobile or truck tires, are preferably filled at a relatively high rate; however, low volume devices such as bicycle tires and sports equipment are more safely filled at a slower rate to avoid overinflation and possible rupture or other damage.
The provision of such an air supply imposes an expense on the operator of the automobile service station or other establishment. Not only is a capital investment necessary to provide the air supply equipment, but also an operating expense is involved, generally for electricity to run a compressor, and maintenance costs are incurred. In order to more equitably apportion such costs to users, it is desirable that the air supply require payment of a charge to enable its operation, rather than burying the expense of the air supply in the prices of other goods sold by the service station, such as gasoline and motor oil.